Effect of temperature on the growth of alfa-PbO2 nanostructures

Ordered arraysof -PbO2 nanostructures weregrown by galvanostatic anodic deposition into the channels of alumina templates. Electrodepositions were performed in an aqueous solution containing lead acetate and sodium acetate at pH5.4. Bath temperature and electrodeposition time were varied to check their effect on the growth of nanostructures. It has been found that filling of alumina pores is independent of the time and electrodeposition temperature, whilst height and growth kinetics of nanostructures vary with both parameters. Temperature greatly influences morphology: wires grown at room temperature consisted of clusters of particles, leading to poorly compact structures, whilst at 40 ◦C the formation of compact wires was observed, some of them being partially hollow. Finally, nanowires with avery regular and dense structure were obtained at 60 ◦C. Also crystalline structure changes with temperature: polycrystalline nanostructures, with a preferential orientation and an average grain size of 21 nm, were obtained at room temperature, whilst at higher temperatures, wires grew almost exclusively along the plane (2 0 0) with an average grain size of approximately 28 nm. Real surface area of nanowires was eval- uated from the FEG-SEM images, and it was found two orders of magnitude greater than the geometrical one.